The teenage midfielder, who is relishing his more advanced role, has revealed that the Nerazzurri's new boss is an even more impressive trainer than he had imagined
The San Siro outfit made a stirring start to last season and looked like genuine Scudetto contenders in October before suffering a dramatic collapse that ultimately cost Andrea Stramaccioni his job.
Mazzarri has been brought in as his replacement and Kovacic has revealed that the former Napoli boss has wasted little time in imposing his ideas and rigorous training programme upon his new players.
"He is a hammer," the Croatia international told Tuttosport. "I said before he arrived that he was a great coach. Well, I was not wrong!"
Kovacic has also been enthused by Mazzarri's decision to employ him in a more advanced position, similar to that undertaken by Napoli's Marek Hamsik.
"I'm ready to put into practice everything that my coach wants to teach me," the 19-year-old midfielder told Tuttosport. "I will do my best to make the most of that position in the field.
"In that position I can give my best; I like it. Hamsik is a great player, but I do not want to be him.
"I want to be myself, for the good of Inter, and to give my maximum on the pitch."
However, despite his renewed enthusiasm for the new campaign, Kovacic freely admits that Inter can ill afford to get ahead of themselves, given Juventus look well placed to win a third consecutive Serie A title.
"They are a great team that gets better every year," the former Dinamo Zagreb playmaker acknowledged.
"We, instead, are a squad that must just think about playing better and not making any claims about the possibility of winning the Scudetto.
"We must not put pressure on ourselves, but work calmly and think only of improving in respect to last year."
Kovacic only arrived at Appiano Gentile during the January transfer window but has already established himself as one of the most exciting young players in Italian football.